It is known to connect an electric motor such as an electronically commutated EC-motor or the like to a DC-voltage source via a control circuit or inverter, wherein the coil ends of the stator windings are each connected via a power switch to the one connecting terminal of the voltage source and via a further power switch to the other connecting terminal of the voltage source. The control unit switches the six power switches in such a manner that a rotating field results for the rotor in the stator of the motor and entrains the rotor.
In a handheld electric work apparatus, battery packs with high power density are used, that is, for example, battery packs with cells chemically based on lithium. Thus, multiple lithium-ion cells, lithium-polymer cells or similar cells are connected to each other in a battery pack in order to provide a battery pack having high output voltage and high capacity. If such a battery pack is connected to a defective drive circuit, high currents can already flow while the motor is being connected or switched on, and these high currents can damage the electronic circuit as well as the motor. Thus, it is expedient to check whether the electronics are functioning properly prior to applying the battery voltage, in order to protect the electronics per se and/or the motor.